How does the LED display fan work?

What's amazing is that the above pattern actually changes. I'm very curious. How can I tell you ??

The conversion rate is used to calculate the variation frequency of the LED lamp.
This is similar to the display principle of the old CRT.
For example, when the fan speed is 60rpm, it is 60 laps per minute and 1 lap per second (of course, the actual speed is much faster, how can we get 600 rpm ).
The fan has a string of LED lights along the radius (or multiple strings, only one string is discussed here ). It is assumed that there are 10, ranging from the axis to the fan blade edge from 1 to 10. Then we assume that the LED light is 0 degrees above the fan at 0 seconds.
If you want to display the effect of on the fan, you need to light 1-10 at 0 seconds, 0.5 seconds to light up 1-5 to show the hour hand, then 1-10 to show the minute hand, 1.5 seconds to light up 1-5 to show the hour hand, and so on, in this way, the human eye will accept a complete clock image.
The complex pattern is also like this, as long as you know the three points:
1. Initial Phase of LED light
2. Fan rotation speed
3. Current Time
You will be able to know the position of the LED light at a certain time point. As long as different LED lights are lit at different positions, a complete pattern can be formed.
The flashing of a string of LED lights may be very powerful, but with the increase in the number of strings, the flashing will gradually improve

 

Source: http://www.zhihu.com/question/21057933